The subscriber to a telephone system has the responsibilities that go with the instrument put into his possession, which not only involves the safe keeping of the instrument but the payment for its use. That is, the calls which are made from a service telephone are monitored and the subscriber is billed therefor dependent upon the number of calls and the distances involved etc. As a practical matter there are many subscribers who are at a decided disadvantage in this respect, as they have no effective way to prevent unauthorized calls from the phone service which they supposedly control. Reference is made to the many situations where a telephone is unattended by the subscriber and thereby made available to unauthorized persons who are prone to take advantage of the situation. For instance, there are places of business which must be left open to the public and where it is necessary for the subscriber to have a telephone in order to conduct business, it being impossible to guard such a telephone at all times. Consequently, unauthorized persons are prone to take advantage of such a subscriber and utilize the telephone to make expensive phone calls, unknown to the subscriber. It is such unauthorized calls with which the present invention is concerned, it being a general object to secure a telephone instrument so that it cannot be employed to make unauthorized calls.
The telephone instrument involves a base and a hand-set that normally rests upon the base when not in use. In the resting position, the hand-set opens a switch that disconnects the instrument from the telephone system. The telephone instrument is characterized by a dial by which selective combinations of numbers can be imposed upon the system in order to complete a call to another telephone and it is an object of this invention to render such a dial inaccessible and inoperable by means of a removable attachment to the instrument and which can be locked into place thereon by the subscriber.
A prerequisite of making and receiving a telephone call is the lifting of the receiver or hand-set, by which a normally open switch is closed by means of releasing plungers exposed within the recesses of the cradle provided as a resting place on the base. Since it is an object of this invention to restrict calls to those which are authorized, it is also an object to permit lifting of the hand-set under all circumstances to both receive and to make certain restricted calls.
The present state of the art telephone instrument involves a digital push button dial that is characterized by several rows of buttons, or touch plates, representing the numbers one (1) to nine (9) and zero (0), and/or the letters "A" through "Z" of the alphabet. Also buttons for additional telephonic functions. For example, a typical dial format involves three rows of four buttons each, offering two button functions in addition to the numerical and letter systems. Accordingly, it is an object of this invention to render a push button dial inaccessible by said removable means that can be locked to the telephone instrument when circumstances require it.
The availability of a telephone instrument is often imperative for emergency situations, and though unauthorized calls are not to be permitted, nevertheless a person may be in dire need to use a telephone for legitimate reasons such as to call the police, the fire department or an ambulance etc. Therefore, it is another object of this invention to provide a removable security attachment that can be locked into position over the dial with the exposure of certain buttons which are reserved for emergency calls only. In this respect, at least seven digits must be used to place an ordinary call, and as many a four more digits for long distance calls. However, the communications systems have adopted a universal code call involving one or two digits and presently for example the digits one (1) and nine (9), using the number combination nine-one-one, or "911", a number used to complete an emergency call. It is another object therefore to provide the ability to make an emergency code call, even though all other calls are made impossible. With the present invention, there is an attachment that is removeably locked onto the base of the telephone instrument, to cover the dial while permitting normal use of the hand-set which actuates the operational switch that connects the instrument into the telephone system.